import re

# ret = re.findall('w\w{2}l','hello world')
# print(ret)
# 
# #cannot match \n ;just cannot match \n
# ret1 = re.findall('w.l','hello w\nld')
# print(ret1)


# ret1 = re.findall('b*','abb')
# print(ret1)

ret1 = re.findall('\d{3}','123445')
print(ret1)

